By default, Python is installed to the folder "C:\Python27". If
you decide to put it somewhere else, note down where. You'll
need this folder in a minute.

2. Connecting Python with Windows

The next step is connecting Python with Windows.
You can do this by adding the
Python folder to your Windows Path.

The Path is a list of folders that Windows checks when it
looks for a program. You can modify it by right-clicking "My
Computer" in the start menu, then clicking "Properties", and then clicking "Advanced system
settings" in the left bar.
Click "Environment Variables..." in the menu that comes up, and find
"Path" in the bottom window (named "System variables"). Add the
text

;C:\Python27;C:\Python27\Scripts;

to the end of your Path. (If you installed Python in a custom
folder, use that folder instead of "C:\Python27".)

This tells Windows to look in your Python folder, and two subfolders, when you run a
command. (The semicolons are used to separate different folders.)
This will let you run Python programs and manage your Python installation.

3. Python libraries

You now have Python installed and set up. The last step is to add
a package manager, which will let you use Python's open-source libraries.

First, if you want to use numpy or scipy, you should download and install them directly. You can do so on the SciPy site. Make sure to download the right files (they should be .exe's) for your version of Python.

The standard Python package manager is called pip. To
get it,
install
distribute
and then
pip.
(Use the files ending in "win32-py2.7.exe". If
you're not using 32-bit Python 2.7, you'll need different versions.)

When you want to install a Python package, run "pip
install <package name>" from the windows command line. (You can get
to the command line by typing "cmd" in the Windows search bar. If
you had the command line open before you changed your path, you
should restart it.)
Some packages won't install properly with pip, in which case you
should use its predecessor, easy_install. This was installed
alongside pip.

For example, you may want to install numpy, a numerical
computation engine, to perform scientific computations. To install it,
run "pip install numpy" from the command line. If you
receive an error, run "easy_install numpy" instead. This will put
numpy on your system.

To check that everything's worked so far, click your Start bar, go to "Python 2.7",
and click "IDLE (Python GUI)". A window named "Python Shell" will
come up, waiting for you to enter commands next to a prompt:

Type in "import numpy" and hit Enter. If Python comes back with
another prompt after a second, everything's working correctly:

4. Getting Started

Congratulations! You've set up Python.
You're ready to start coding. If you're working with DataNitro, check
out our Quickstart
for an introduction. If you're learning Python, here are some good
resources to get started:

A note on Python versions

This page recommends the latest version of 32-bit Python 2. You
should use
this, rather than 64-bit Python or Python 3, unless you have a reason
for switching. If you're not which version to use, stick with 32-bit
Python 2.

You can also install multiple versions of Python if you want to try
out more than one. The command line will use the one that comes
first in your Path, and double-clicking on .py files will run
whichever one you install last. (To avoid this, uncheck "Register
Extensions" while you're running the installer.)

Why Python 2 instead of Python 3?
Python 3 isn't backwards compatible with Python 2, and there are still
a lot of libraries that don't work with Python 3. Just as
importantly, if you're going to work with any existing Python
code, it'll almost certainly be Python 2.
You can use Python 3 if you won't need to work with any existing code, and you know that
the libraries you need are available in Python 3.

Why 32-bit instead of 64-bit?
Just like with Python 3, there are a lot of libraries that
don't support 64-bit Python.
You should use 64-bit Python if you need to perform very large
computations, and you know that the libraries you need have 64-bit
versions available.